Circuit breaker locking mechanism



Nov. 29, 1966 A, R. NORDEN 3,288,954

CIRCUIT BREAKER LOCKING MECHANISM Filed April 28, 1964 T1 @240. T1 cilia.

I I NVENTOR mam 021W United States Patent M 3,288,954 CIRCUIT BREAKER LOCKING MECHANISM Alexander R. Norden, New York, N.Y., assignor to Murray Manufacturing Corporation, Brooklyn, N.Y., a corporation of New York Filed Apr. 28, 1964-. Ser. No. 363,233 9 Claims. (Cl. 200-42) This invention relates in general to a circuit breaker or circuit controlling instrumentality, and in particular, to a provision for locking the operating handles of such devices in either the ON or OFF position.

It is often advisable, if not necessary, to protect a circuit breaker against undesirable switching, which might occur either surreptitiously or accidentally, by locking the operating handles thereof. Conventional locking provisions employ (in conjunction with padlocks) such diverse arrangements as locking ears attached to, or integrally formed out of, the breaker enclosure cover; a locking ear retained between the enclosure cover and breaker; a pivotal locker arm mounted within the breaker assembly; or a snap-in member which may be latched in a recess in the breaker body.

While these arrangements fulfill the basic functional requisites, each possesses inherent disadvantages. The first two require that the accumulation of tolerances between the breaker, metal enclosure and cover be sufficiently small to limit the degrees of handle movement within that which would not permit actuation of the internal mechanism; particularly where such arrangements depend upon the diameter of the padlock shackle for limiting handle travel. Moreover, and this applies to all but the last of the aforementioned arrangements, the provision of a padlock receiving member as an integral part of the breaker assembly is economically sound only on larger breaker ratings where the need is common. On lower ratings, where the need is only occassional, the addition of a lock receiving means on all units is obviously impractical.

A partial solution, which obviates the foregoing objections, is the elongated snap-in member previously alluded to, adapted by a resilient lanced latch to engage a corresponding groove in the breaker casing. This arrangement, however, is only feasible where the wall thickness of the breaker casing is sufficient to accommodate the recess for the snap-in member as well as the additional space required for the locking lance groove; the latter of which must have enough depth for a secure latch. Needless to say, if the groove is too shallow, albeit due to the casing thickness, the required latching effect is defeated, either directly or indirectly by repeated chipping, and the snap-in member may be removed.

Accordingly, it is the object of this invention to provide a locking provision for the handle of a circuit breaker of substantially standard construction: the breaker being susceptible of supply and use without the locking provision and without modification in its external or internal dimensions.

It is another object of this invention to provide a circuit breaker locking provision which maybe simply and quickly installed, either during the manufacturing or in the field, and which once installed both firmly and reliably resists removal.

It is a further object of this invention to provide a locking provision which once installed may be disposed in a non-functional position for unobstructed handle operation.

Briefly, the invention is predicated upon the concept of a handle obstructing locking member insertable in a companion recess in a circuit breaker, characterized by the constitution of said member of a flat ductile metal,

3,288,954 Patented Nov. 29, 1966 and the formation of said recess with camming surfaces for deforming said member and a necked portion for preventing its removal once deformation has taken place.

The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will best be understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an exploded perspective illustrating the breaker, locking member insert, and lock relationship;

FIGS. 2(a) and 2 (b) are front elevation and sidecross-sectional views, respectively, of the locking member insert;

FIG. 3 is a plan view showing locking member deformation upon insertion; and

FIG. 4 illustrates the deformed locking member retained in handle obstructing position.

Referring now to FIG. 1, there may be seen a circuit breaker 10 composed of two contiguous pole pieces 11 and 13, interconnected for simultaneously dependent operation in any of the manners well known to those versed in the art. Suffice it to say, the trippable mechanism in either pole is actuated in response to an overload tripping of the other pole. Each pole is of the trip-free type in which notwithstanding the rigid maintenance of the handle in the ON position, the respective contacts are free to separate on overload. The pole handles 11 and 13', each pivoted between an ON.and OFF position, are coupled for joint setting and resetting by the connecting cylinder 15.

The housing for the internal mechanisms of the pole pieces are of an insulating material, such as Bakelite, and are each composed of a hollow case, through which the pivotal handles extend, and an afiixed cover. Pursuant to the invention, and located between the extremes of handle travel, is a locking-member-accepting recess 17, longitudinally formed within the adjacent cover or case (or both) of the contiguous pole pieces. For purposes of illustration the second location has been selected. The precise shape of this recess as well as the function and effect of the locking member insert 18 and padlock 19 will be described hereinafter with reference to FIGS. 2 through 4.

FIGS. 2(a) and 2(b) show the locking member 18 for insertion in the corresponding recess 17. It is essentially a flat stamping of ductile metal, the form of which may be described in three sections, arbitrarily designated the head, body and feet. The head section comprises an aperture 23 through which the padlock shackle may be passed, and a lanced stop 21, the purpose of which will be explained. The body portion 24 connects the head, via a triple necked section 25, to the feet 27 and 29.

The recess 17 which may be seen in FIG. 3, is flat and of sufiicient depth for slidably accepting the locking member. It is composed essentially of two sections 30 and 32 separated by the ridges (or neck) 31 and 31'. The upper section 30 is dimensioned for receiving the locking member head; the feet 27 and 29 passing through this section (as shown in the figure by the dashed lines) and between the ridges which are spaced by an amount sutficient to admit them while in their parallel or H-shape. Upon further travel of the locking member, the ends of the feet 27 and 29 encounter the camming surface 33 and 35 located in the lower recess portion 32. Final travel of the locking member into the recess (until the stop 21 abuts the outside of the adjacent pole piece cover) causes the feet and connecting neck to deform into an A or arrowhead shape the upper part of the feet flaring outwardly as the leading tips of the feet cam inwardly. In this positiJn, the locking member is non-functioning and the handle cun- 3 necting cylinder clears the locking member head for travel either to the ON orOFF positions.

FIG. 4 shows the locking member in obstructing position. The legs having flared, the member is now pulled upwardly until the upper feet tips engage the lower ridge surfaces. The head aperture 23 has now cleared the recess, and the padlock shackle 1.9 may be passed therethrough to prevent retrograde movement of the member 18. The locking member head now obstructs the connecting cylinder 15 and hence handle travel. Removal of the shackle allows head withdrawal and unobstructed operation.

It is to be noted that with the disclosed arrangement the greater the pullout force, the greater is the tendency for the upper feet tips to spread and maintain their position.

While the foregoing describes a preferred embodiment it is to be clearly understood that the invention is not so limited. For example, the locking member may be employed with any circuit controlling instrumentality having a handle and capable of providing a recess for the locking member. It is also possible, although such an arrangement is not necessarily a preferred one for a single handle to be maintained in position by the locking member; the padlock shackle rather than the member head acting as a travel limiting obstruction to the-handle. Further, the locking member may be formed with the same head and body dimensions, in which case the disclosed ridges will take the form of a flange, in either case this obstruction may be generically termed a flange.

Sufiice it to say that these and many other modifications will be apparent to those skilled in the art and the foregoing description is exemplary only and is not intended as a limitation on the scope of my invention as set forth in the objects thereof and in the following claims, for example, only onehalf of the above described H-shape may be employed in conjunction with a single non-symmetrical camming surface.

What is claimed is:

1. A deformable locking member for insertion in a companion recess of a circuit controlling instrumentality for locking the actuating handle thereof in a predetermined position, comprising the integral arrangement of a flat and relatively thin head section containing an aperture therein, an H-shaped section, and an elongated body section connected between said head section and the crossbar of said H-shaped section.

2. The combination with the deformable locking member claimed in claim 1 of a circuit controlling instrumentality having an enclosing insulator housing and an actuating handle passing through said housing for manual displacement between OFF. and ON positions, said housing including means adjacent said handle for receiving, deforming and retaining said locking member.

3. The combination claimed in claim 2 in which said means is a recessed passage in said housing comprising a portion dimensioned for snugly admitting the locking member H-shaped section therethrough, and an interior V-shaped camming section for deforming said H-shape to an A-shape, thereby preventing retrograted of the latter through said snugly dimensioned portion of said passage.

4. The combination claimed in claim 3 in which said V-shaped section is removed from said snugly dimensioned portion a distance sufiicient to allow two positions of said locking member, one with aperture exposed and the second with all but a small part of said locking member concealed in said recessed passage.

5. The combination with a permanently deformablelocking member of a circuit controlling instrumentality having an enclosing insulator housing, an actuating handle passing through said housing for manual displacement between OFF and ON positions, and a recessed housing passage adjacent said handle for receiving, deforming and retaining a deformable locking member insert, said passage including flange means for snugly admitting an undeformed section of said locking member therethrough and an interior camming section for permanently deforming said locking member section and thereby preventing its retrograde through said flange means.

6. The circuit controlling instrumentality claimed in claim 5 in which said interior section of said passage is V-shaped.

7. In a circuit breaker having a plurality of contiguous insulator-enclosed poles with commonly coupled actuating means movable between defined positions for the joint setting and resetting of said poles, the improvement for locking the actuating means in either of said defined positions comprising in combination: a recessed passage adjacent said actuating means and defined Within the insulation wall disposed between adjacent poles; and a permanently deformable locking member insertable in said recessed passage; said recessed passage including means for permanently deforming said locking member and flange means for limiting said locking members retrograde to a projected actuating-means-obstructing position.

8. The improvement claimed in claim 7 in which the de formed locking member is longitudinally slidable in said passage between a projected actuating-means-obstructing position and a retracted actuating-meansclearing position, said locking member containing an aperture therein for receiving a member retaining said locking member in the projected position.

9. The improvement claimed in claim 8 in which said locking member comprises a deformable foot section in the shape of an H; and said recessed passage contains a neck portion for snugly admitting said H-shaped foot section therethrough, and an interior V-shaped camming portion for deforming said foot section to an A-shape thereby preventing its retrograde through said neck portion.

References Cited by the Examiner UNITED STATES PATENTS 2,943,162 6/1960 Norden 20044 ROBERT K. SCHAEFER, Primary Examiner. H. HOHAUSER, Assistant Examiner. 

5. THE COMBINATION WITH A PERMANENTLY DEFORMABLE LOCKING MEMBER OF A CIRCUIT CONTROLLING INSTRUMENTALITY HAVING AN ENCLOSING INSULATOR HOUSING, AN ACTUATING HANDLE PASSING THROUGH SAID HOUSING FOR MANUAL DISPLACEMENT BETWEEN OFF AND ON POSITIONS, AND A RECESSED HOUSING PASSAGE ADJACENT SAID HANDLE FOR RECEIVING, DEFORMING AND RETAINING A DEFORMABLE LOCKING MEMBER INSERT, SAID PASSAGE INCLUDING FLANGE MEANS FOR SNUGLY ADMITTING AN UNDEFORMED SECTION OF SAID LOCKING MEMBER THERETHROUGH AND AN INTERIOR CAMMING SECTION FOR PERMANENTLY DEFORMING SAID LOCKING MEMBER SECTION AND THEREBY PREVENTING ITS RETROGRADE THROUGH SAID FLANGE MEANS. 